The present invention relates generally to the field of rotary die embossing, and more particularly to rotary embossing dies and a method for making and using such dies.
Although they are relative newcomers to the centuries-old printing and embossing trade, rotary embossing machines and their attendant dies have been manufactured and used for numerous years. Conventionally, rotary embossing dies are formed of resinous or metallic material and cover, or are integrally formed with, the surface of an embossing machine die-cylinder. Additionally, conventional metallic dies are generally thick (approximately 1/4" to 1/2") and, therefore, heavy and difficult to manipulate.
Conventional embossing dies have been successfully used in the embossing field. However, because they cover, or are integrally formed with, the entire surface of a die cylinder, they are often cumbersome and costly to use. Thus, if an embossing design is required to be changed or an embossing die needs to be replaced, the die cylinder must be removed from the embossing machine and replaced with a new cylinder (if the embossing die is integrally formed with the die cylinder), or the embossing die must be removed from substantially the entire surface of the die cylinder. Because separate die cylinders are often required for each embossing design, and the replacement of embossing dies is a time consuming process, the use of conventional rotary embossing dies results in increased die costs and lengthy embossing machine down-time when changing dies.
A typical three-step process for forming rotary embossing dies includes first etching or otherwise forming a desired embossing shape or design on a metallic plate. Second, a negative image of the embossing design is formed on a rubber mat (or other flexible material) by a flexoplating or etching technique, as is commonly known in the art. Lastly, the rubber mat is placed face-up (i.e., with the design exposed) in a die mold and an epoxy material is injected into the mold to form an epoxy die plate having a positive image of the design. The resultant epoxy rotary die plate is then used on a rotary embossing machine to form embossed images of the design originally present on the metallic plate on paper, or other suitable material.
While the above-described method of forming rotary embossing dies has produced satisfactory rotary embossing dies, there are a number of associated problems and/or disadvantages. For example, the sharpness of the original design is reduced through transfers of the design to a flexible, soft material such as the rubber mat and, subsequently, to the epoxy die plate. This reduction in sharpness directly translates to the final embossed product and results in embossments that are not as clear, sharp and distinct as the desired original design. Also, because epoxy rotary die plates do not wear as well as regular metallic die plates, there is a frequent need to replace the epoxy die plates, which further increases down-time and costs.